Digital two-wire irrigation control system with feedback

For use in a digital irrigation control system in which both alternating-current power and control signals are transmitted along the same conducting lines to a number of decoders, and confirmatory on/off feedback signals are transmitted back from the decoders, encoding apparatus comprising:

• means for encoding and transmitting blocks of control information, including decoder addresses and on/off codes, onto the lines, by selective suppression of part of the power signal;
• means for detecting confirmatory on/off feedback signals from the decoders each feedback signal being transmitted during a temporary interruption of the power signal following each corresponding transmission of a block of control information;
• and
• means for storing and displaying information contained in said feedback signals as an indication of on/off status conditions at the decoders.

A digital irrigation control system in which an alternating-current power signal and control information are transmitted along the same conducting lines, said system comprising:

• encoding means for encoding and transmitting blocks of control information, including decoder addresses and on/off codes, onto the lines, said encoding means being operable to selectively suppress part of the alternating current power signal and thereby to encode the control information;
• decoding means for recovering the blocks of control information from the conducting lines, comparing each recovered decoder address with an address associated with said particular decoding means, and operating at least one valve in accordance with received on/off codes addressed to said decoding means;
• means coupled with said decoding means, for transmitting, during intervals of temporary interruption of the power signal, feedback signals corresponding to said on/off codes addressed to said decoding means;
• means coupled with said encoding means, for detecting said feedback signals received following transmissions of blocks of control information;
• and
• means for storing and displaying information contained in said feedback signals as an indication of on/off status conditions at the decoders.

For use in a digital control system in which both power and control signals are transmitted along the same conducting lines from an encoder to a plurality of remote decoders, for the control of a plurality of switchable devices, portable control apparatus connectable to the conducting lines to control the switchable devices in conjunction with the encoder, said apparatus comprising:

• means for decoding control signals transmitted by the encoder;
• means responsive to decoding of control signals addressed to said portable control apparatus, for transmitting feedback signals of a first type to the encoder to indicate that said portable control apparatus is connected to the lines;
• manually operable means for selecting which decoders are to be manually controlled;
• and
• means for transmitting feedback signals of a second type to the encoder to indicate which decoders are to be manually controlled from said portable control apparatus;
• whereby the transmission of control signals from said encoder is controlled by said portable control apparatus so long as said apparatus is connected to the lines.

For use in a digital irrigation control system in which both power and control signals are transmitted along the same conducting lines from an encoder to a plurality of remotely located decoders, for the control of a plurality of switchable valves, apparatus for the control of said system from any desired location, said apparatus comprising:

• portable control means connectable to the conducting lines to control the switchable valves in conjunction with the encoder, said portable control means including
• means for decoding control signals, including decoder addresses and on/off codes, transmitted from the encoder,
• means responsive to decoding of control signals addressed to said portable control means, for transmitting feedback signals of a first type to the encoder to indicate that said portable control means is connected to the lines,
• manually operable means for selecting decoder control functions, and
• means for transmitting feedback signals of a second type to indicate control functions to the encoder;
• and
• control means included within the encoder and including
• means for detecting feedback signals of the first type and thereby determining whether said portable control means is connected to the lines,
• means for decoding feedback signals of the second type, and
• means for selecting for transmission on/off codes as determined by said feedback signals of the second type instead of as determined by a normal preselected sequence of valve operations.

A digital irrigation control system in which both power and control signals are transmitted along the same conducting lines to control a plurality of switchable valves, said system comprising:

• at least one decoder for decoding control signals, including decoder addresses and on/off codes;
• means at said decoder for transmitting feedback signals of a first type indicating that an on/off code addressed to said decoder has been received;
• portable control means connectable to the conducting lines to control the switchable valves, said portable control means including
• means responsive to control signals transmitted along the lines and addressed to said portable control means, for transmitting feedback signals of the first type, indicating that said portable control means is connected to the lines,
• manually operable means for selecting decoder control functions, and
• means for transmitting feedback signals of a second type, to convey the selected decoder control functions;
• and an encoder including
• means for detecting and storing feedback signals of said first and second types,
• means for selecting for transmission on/off codes from a predetermined sequence of commands, if said portable control means is not connected to the lines,
• means for selecting for transmission on/off codes determined by said feedback signals of the second type, if said portable control means is connected to the lines, and
• means for encoding the selected on/off codes and decoder addresses onto the lines for transmission to said decoder and said portable control means.

A method of controlling operations of a plurality of switchable devices in a digital control system in which both power and control signals are transmitted along the same conducting lines from an encoder to a plurality of decoders, said method comprising the steps of:

• encoding control signals for transmission with an alternating-current power signal along common conducting lines to the decoders, said encoding step including selectively rectifying the power signal and thereby selectively suppressing current flow in one direction to encode the control signals in a binary fashion;
• decoding the control signals at least one decoder;
• operating a switchable device at the decoder in accordance with the decoded control signals;
• and
• transmitting a feedback signal back to the encoder during a temporary interruption of the power signal, following the receipt of control signals intended for the decoder, to indicate the state of the switchable device at the decoder after said operating step.

For use in a digital control system in which both power and control signals are transmitted along the same conducting lines from an encoder to a plurality of decoders, a method for the control of switchable devices in the system from any desired point along the conducting lines, said method comprising the steps of:

• connecting a portable operator at a desired location along the conducting lines;
• periodically transmitting from the encoder a control signal addressed specifically to the portable operator;
• manually selecting a control function at the portable operator;
• monitoring at the portable operator all control signals transmitted by the encoder;
• transmitting feedback signals to the encoder, in response to control signals monitored by the portable operator, the feedback signals being indicative of the selected control function;
• and
• automatically performing the selected control function at the encoder instead of performing control functions in accordance with a predetermined schedule.